The present invention relates to a device and a method for driving an electro-optical panel, such as an organic EL (electro-luminescent) panel, an electro-optical device comprising the electro-optical panel and the driving device, such as an organic EL device, and a variety of electronic apparatuses having the electro-optical device.
In this type of electro-optical device, a plurality of pixel units each comprising active elements, a storage capacitor, and an electro-optical element driven according to electric charge stored into the storage capacitor is arranged in an image display region on a substrate, and a current program is executed to actively drive the plurality of pixel units. By executing the current program, flickers generated by the difference in threshold voltage between the active elements in the pixel units are suppressed, so that high-quality image display can be performed.
At the time of current programming, in each pixel unit, a current that corresponds to a gray scale level to be displayed in the pixel unit is supplied through a source line to the storage capacitor, and the electric charge is stored according to the supplied current. Here, when the current value of the source line is low, a parasitic capacitor of the source line as well as the storage capacitor should be charged with a low current. For this reason, it is difficult to store a predetermined electric charge in each pixel unit for a short time.
Therefore, in order to increase the current value of the source line at the time of current programming, current mirrors comprising thin film transistors (hereinafter, referred to as “TFTs”) are provided to the respective pixel units as described in Patent Document 1 described below. Alternatively, pixel units in a plurality of rows arranged along the source lines are selected according to Patent Documents 2 and 3. In particular, according to Patent Document 2, a current ten times as large as the current supplied to one pixel unit is provided to the source line in response to selected k rows of pixel units (where, k is a natural number greater than or equal to 2).
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2003-99001.
[Patent Document 2] Japanese Unexamined Patent Application Publication No. 2003-150082.
[Patent Document 3] Japanese Unexamined Patent Application Publication No. 10-198313.